Bob K0NR (email list) wrote:
amsat-bb-request@amsat.org wrote:
It seems improving the 2.4 dB of insertion loss of the diplexer would be a better strategy (although not necessarily easy in the space available) than attempting to modify what is very mechanically sound antenna.
73, Joe kk0sd
I am surprised that the duplexer/diplexer (take your pick) has that much loss. Has anyone verified this via a direct measurement (such as via a network analyzer)?
Bob K0NR
I don't have a network analyzer handy, so I did an A/B test driving the Power Meter on my HP 8920A using a handheld radio. At 435 MHz, the measured power with just a cable connection is 2.5 W. With the Arrow duplexor inserted, the power is 1.8 W. This implies a loss of 10 log (1.8 /2.5) = -1.4 dB, more than I would have expected.
How accurate is this measurement? I dunno, probably no worse than 0.5 dB. This deserves further investigation.
73, Bob K0NR